The Landkreuzer P 1500 Monster was a German super-heavy tank designed during World War II, representing the apex of the Nazis' extreme tank designs.
On 23 June 1942 the German Ministry of Armaments proposed a 1,000 tonne tank – the Landkreuzer P. 1000 Ratte. Adolf Hitler himself expressed interest in the project and go-ahead was granted. In December the same year, Krupp designed an even larger 1,500 tonne tank – the P 1500 Monster.
This "land cruiser" was a self-propelled platform for the 800mm Schwerer Gustav artillery piece also made by Krupp – one of the largest artillery weapons ever built. Their seven tonne projectiles fired up to 37 km (23 miles) and were designed for use against heavily fortified targets.
The Landkreuzer P. 1500 Monster was (138 ft) long, weighing 1500 tonnes, with a 250 mm hull front armor, 4 MAN U-boat (submarine) diesel engines, and an operating crew of over 100 men.
The main armament was to be an 800 mm Dora/Schwerer Gustav K (E) railway gun, and with a secondary armament of two 150 mm sFH 18/1 L/30 howitzers and multiple 15 mm MG 151/15 machine guns.
Development of the Panzer VIII Maus had highlighted significant practical problems associated with very large tanks, such as their destruction of roads, their inability to use bridges and the difficulty of strategic transportation by road or rail. The larger the tank, the bigger these problems became, to the point where they were insurmountable. However the Nazis overcame these problems with such a large size the engineers reasoned that it would be able to ford any river or use explosives to move the river.
With such a massive need for steel and other such raw materials it was proposed to be built by the Navy who had more experience making such large vehicles. Hitler was persuaded, when he was presented with the idea of the two Landkreuzers to cut back on the P-1000 Ratte which was less likely to be successful as it was designed as a tank. In the end 15 of these were built while all 15 of the Dora artillery pieces were recycled into the project. Each of them took around three months to complete but seven shipyards were in use to make them so all were completed within a year an incredible pace.
Hitler was very pleased at losing his "archaic railway guns" which he claimed had "no viable use until the world was paved with railway track!". He sent many of them to fight on the Eastern Front and when the time came he surrounded Paris with them to try and defend it.
Other than the Eastern front they saw very little action and were just glorified artillery.
None were destroyed in combat though none were captured or found after the war. This lead to the rise of the Fourth Front Theory in which Hitler moved millions of men and soldiers to an undisclosed location to prepare for a fourth front.